Medical monitoring involves monitoring the body of a subject to determine the state of health of the subject and to detect, identify, and diagnosis changes or abnormalities in the state of the body which may be indicative of problems or for treatment evaluation. Medical monitoring may involve, for example, the motion of a subject's body, temperature or chemical changes of the subject's body, and/or audible or electrical signals generated by the subject's body. For example, electroencephalography (EEG) is a form of medical monitoring wherein the electrical potentials of the subject's brain are monitored by attaching electrodes to the subject's scalp. In electromyography (EMG), electrical activity generated in the subject's muscles is monitored using surface and/or needle recording electrodes. Medical monitoring may take place when a subject is at rest, in motion, or during the performance of a medical procedure. In some cases, medical monitoring involves monitoring the response of the subject to a stimulus. For example, evoked potential (EP) monitoring may be used to detect the electrical response of a subject's brain to audible, visual, or electrical stimuli. Medical monitoring involving stimulus and response detection may be used in combination with EMG and various other medical monitoring methods as well.
Monitoring of the various physiological signals generated by a subject's body is typically performed using dedicated devices and/or systems. For example, EEG monitoring may be performed using a dedicated EEG monitoring system, by attaching electrodes to a subject to detect the electrical potentials of the subject's brain, amplifying and filtering the signals received from the electrodes for the desired frequency range of interest for EEG analysis, and providing the amplified and filtered signals to an EEG analysis system including software for further manipulating the EEG signals for analysis and display on an EEG system monitor. Similarly, EMG monitoring may be performed using a dedicated EMG monitoring system, by placing electrodes on the subject to detect electrical activity generated in the subject's muscles, amplifying and filtering the signals detected by the electrodes for the desired frequency range of interest for EMG signals, and providing the amplified and filtered signals to an EMG analysis system including software for further manipulating the EMG signals for analysis and display on an EMG system monitor. Other signals of interest, e.g., vital signs, may be monitored in a similar manner, with a separate dedicated system provided for each type or modality of monitored signal of interest. Each such dedicated monitoring system may include or be connected to a system for providing stimulus to a subject, and for analyzing the particular detected signal of interest in response to the stimulus provided.
To provide a fall range of diagnostic capability, a doctor's office or operating room, ICU or ER must have available systems for monitoring various physiological signals. Thus, EEG, EMG, vital signs, and other physiological signal monitoring systems preferably must be readily available. Where the capability for monitoring each different type of physiological signal is implemented in a dedicated system, maintaining a full range of diagnostic capability can be a very expensive proposition. Moreover, in many cases it may be desirable to monitor the various physiological signals generated by a subject's body simultaneously. Thus, it may be desired to monitor simultaneously EEG, EMG, vital signs, and other physiological signals generated by a subject. If each type of signal to be monitored requires a dedicated monitoring system, each system having its own set of electrodes, monitoring and display units, etc., all simultaneously connected to a subject, an operating room or other medical facility will be crowded with equipment, which may interfere with the procedures being performed. More significantly, each such system must be operated independently, and may have its own unique user interface. Thus, critical time and effort may be wasted as a physician or other specialist must constantly switch his attention between different medical monitoring systems in order to monitor various physiological signals of interest.